He has always been a man of paradox. A ferocious intellectual with a kindly face, a scholar in the arena, a German in Italy: Joseph Ratzinger, known to history as Pope Benedict XVI, the 265th bishop of Rome, defies easy categorization. So it was in the beginning, in the early months of his pontificate, when Benedict--variously caricatured as "God's rottweiler" or the "Panzer Cardinal"--chose to initially address the church not about discipline or authority but about love. Issuing his inaugural encyclical (a message intended to be read through the whole church), the successor to John Paul II called on the faithful to be always in charity: "In all humility we will do what we can, and in all humility we will entrust the rest to the Lord," he wrote at Christmas 2005. "It is God who governs the world, not we. We offer him our service only to the extent that we can and for as long as he grants us the strength."

Now, just over seven years later, his strength is gone, and in a striking, even revolutionary act of humility, Benedict has announced his resignation as the Vicar of Christ, effective at 8 p.m. Rome time on Feb. 28. A figure as controversial as John Paul II was popular, Benedict XVI has yet again flummoxed his many critics by becoming the first Pope in six centuries to abdicate the Chair of Peter. And it is now possible that his most enduring act of public witness to the Gospel will be the remarkable spectacle of a prince of the church voluntarily surrendering the things of this world. Just as John Paul II offered a testament of suffering in his last years, Benedict XVI has given us something rare among the most mighty: an example of Christian piety that was quite unexpected.

In caricature, Ratzinger has been about power, about quelling dissent and enforcing orthodoxy. In fact, he has always been a more complicated man, at once a reformer (he was initially supportive of the Second Vatican Council) and a traditionalist. For him, salvation and the promise of the faith--that God and the risen Jesus will one day make all things new--are thrilling prospects that can be understood only by drawing on tradition. For Benedict, as for T.S. Eliot in Four Quartets, the way forward is the way back.

His was not a quiet papacy. Though he met with victims of clerical sexual abuse and did more than his predecessors on the insidious questions about years-long cover-ups, Benedict leaves a church that tends to remain more interested in protecting its priests and bishops than its children. In early days he provoked a controversy with Islam by citing the views of the 14th century emperor Manuel Palaiologos who said, "Show me just what Muhammad brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." Reformers, especially American ones, eager for the ordination of women or a more liberal view of human sexuality got what they expected from Benedict: nothing.